Problem: Divide the following complex numbers: $\dfrac{8}{ e^{7\pi i / 6}}$ (The dividend is plotted in blue and the divisor in plotted in green. Your current answer will be plotted orange.)
Answer: Dividing complex numbers in polar forms can be done by dividing the radii and subtracting the angles. The first number ( $8$ ) has angle $0$ and radius 8. The second number ( $ e^{7\pi i / 6}$ ) has angle $\frac{7}{6}\pi$ and radius 1. The radius of the result will be $\frac{8}{1}$ , which is 8. The difference of the angles is $0 - \frac{7}{6}\pi = -\frac{7}{6}\pi$ The angle $-\frac{7}{6}\pi$ is negative. A complex number goes a full circle if its angle is increased by $2 \pi$ , so it goes back to itself. Because of that, angles of complex numbers are convenient to keep between $0$ and $2 \pi$ $-\frac{7}{6}\pi + 2 \pi = \frac{5}{6}\pi$ The radius of the result is $8$ and the angle of the result is $\frac{5}{6}\pi$.